Scotland Helicopter Crash
Discussion
GadgeS3C said:
Understood - my question was that there seem to be quite a lot of time from the fuel warning to the crash. Would the helicopter have stayed in the air that long with the pilot incapacitated? Is there an autopilot?
Yes - although there is no info on if this was in use at the time.the odd bit is the pilot requested clearance from ATC to re-enter the Glasgow Control Zone at 22:18, and crashed shortly after 22:22.19 (when it was last seen on Radar @400 ft).
on that basis, it was already well into the supply tanks when he requested clearance, and would have had both low fuel warnings up for some time already.
Scuffers said:
Yes - although there is no info on if this was in use at the time.
the odd bit is the pilot requested clearance from ATC to re-enter the Glasgow Control Zone at 22:18, and crashed shortly after 22:22.19 (when it was last seen on Radar @400 ft).
on that basis, it was already well into the supply tanks when he requested clearance, and would have had both low fuel warnings up for some time already.
Ta Scuffers, hadn't read the timings in detail. That is very odd. the odd bit is the pilot requested clearance from ATC to re-enter the Glasgow Control Zone at 22:18, and crashed shortly after 22:22.19 (when it was last seen on Radar @400 ft).
on that basis, it was already well into the supply tanks when he requested clearance, and would have had both low fuel warnings up for some time already.
I've read the report and although I know the sum total of sod all about helicopters it was fairly easy to follow. I just want to make sure I have something right.
The supply tanks did not automatically recharge/refill from the main fuel tank - am I reading that right? So once they were depleted, the pilot had to take action to switch on the pumps which moved fuel from the main tank to the supply tanks, otherwise the engines would ultimately starve of fuel, regardless of how much remained in the main tank?
Have I got that right, or am I way off base?
The supply tanks did not automatically recharge/refill from the main fuel tank - am I reading that right? So once they were depleted, the pilot had to take action to switch on the pumps which moved fuel from the main tank to the supply tanks, otherwise the engines would ultimately starve of fuel, regardless of how much remained in the main tank?
Have I got that right, or am I way off base?
eccles said:
They mentioned on the news that the AAIB are investigating to see if there was anything wrong with indications the pilot was seeing.
It looks like the passage in the bulletin relating to the Central Panel Display System could be key. Reading between the lines, did the pilot get any warnings at all?
Scuffers said:
GadgeS3C said:
This is total speculation from someone that doesn't know what they're talking about
you don't hear that often on PH!
but if the pilot had been incapacitated for several minutes would things not have gone wrong sooner? Or would the passengers have been able to use the radio?
How so?you don't hear that often on PH!
but if the pilot had been incapacitated for several minutes would things not have gone wrong sooner? Or would the passengers have been able to use the radio?
All i am doing is quoting the aib report and parts of the ec135 manual.
TheSnitch said:
I've read the report and although I know the sum total of sod all about helicopters it was fairly easy to follow. I just want to make sure I have something right.
The supply tanks did not automatically recharge/refill from the main fuel tank - am I reading that right? So once they were depleted, the pilot had to take action to switch on the pumps which moved fuel from the main tank to the supply tanks, otherwise the engines would ultimately starve of fuel, regardless of how much remained in the main tank?
Have I got that right, or am I way off base?
Sort if.The supply tanks did not automatically recharge/refill from the main fuel tank - am I reading that right? So once they were depleted, the pilot had to take action to switch on the pumps which moved fuel from the main tank to the supply tanks, otherwise the engines would ultimately starve of fuel, regardless of how much remained in the main tank?
Have I got that right, or am I way off base?
The main tank feeds the supply tanks by gravity untill you get low on fuel, how low depends on the attitude of the copter, as in hovering or moving etc.
Scuffers said:
TheSnitch said:
I've read the report and although I know the sum total of sod all about helicopters it was fairly easy to follow. I just want to make sure I have something right.
The supply tanks did not automatically recharge/refill from the main fuel tank - am I reading that right? So once they were depleted, the pilot had to take action to switch on the pumps which moved fuel from the main tank to the supply tanks, otherwise the engines would ultimately starve of fuel, regardless of how much remained in the main tank?
Have I got that right, or am I way off base?
Sort if.The supply tanks did not automatically recharge/refill from the main fuel tank - am I reading that right? So once they were depleted, the pilot had to take action to switch on the pumps which moved fuel from the main tank to the supply tanks, otherwise the engines would ultimately starve of fuel, regardless of how much remained in the main tank?
Have I got that right, or am I way off base?
The main tank feeds the supply tanks by gravity untill you get low on fuel, how low depends on the attitude of the copter, as in hovering or moving etc.
WinstonWolf said:
Wouldn't a pilot with this level of experience have auto rotated automatically in the absence of warnings?
That's exactly what I've asked but had no reply - I don't understand why he didn't 
As I've mentioned the blades weren't bent which indicates it literally fallen out of the sky and by not too high either based on the fact the cabin was still in tact.
Magog said:
It looks like the passage in the bulletin relating to the Central Panel Display System could be key. Reading between the lines, did the pilot get any warnings at all?
It is best to read the PDF of the report really, it is only 9 pages long and is relatively easy to understand. Here is the relevant part, but it is best to read it in the full context:AAIB Report said:
Recorded data
Data from the helicopter
:
The contents of the non-volatile memory (NVM) from the equipment known to record data have been successfully recovered and are being analysed. The majority of the recorded data have no form of time stamp. So, whilst the order of some of the snapshots can be determined, their relative timing is unknown. Other systems use time references but ones that are not directly linked to UTC.
The Warning Unit has provided information on the order in which warnings were triggered during the flight but not when they occurred. The unit recorded the normal warnings associated with starting the helicopter, followed by a warning free status. It subsequently recorded intermittent LOW FUEL 1 warnings for the left fuel supply tank, then a permanent LOW FUEL 2 warning for the right fuel supply tank. This was followed by a further temporary LOW FUEL 1 warning, before it became permanent for the remainder of the flight. These LOW FUEL warnings are triggered by thermal sensors in the supply tanks.
An alarm gong was also recorded followed by intermittent warnings relating to low rotor rpm. The penultimate warning recorded related to the battery discharging, which occurs when there is insufficient engine-driven generator power. The last warning related to an autopilot system failure. Investigation into the possible causes for the individual warnings is continuing.
Data from the helicopter
:
The contents of the non-volatile memory (NVM) from the equipment known to record data have been successfully recovered and are being analysed. The majority of the recorded data have no form of time stamp. So, whilst the order of some of the snapshots can be determined, their relative timing is unknown. Other systems use time references but ones that are not directly linked to UTC.
The Warning Unit has provided information on the order in which warnings were triggered during the flight but not when they occurred. The unit recorded the normal warnings associated with starting the helicopter, followed by a warning free status. It subsequently recorded intermittent LOW FUEL 1 warnings for the left fuel supply tank, then a permanent LOW FUEL 2 warning for the right fuel supply tank. This was followed by a further temporary LOW FUEL 1 warning, before it became permanent for the remainder of the flight. These LOW FUEL warnings are triggered by thermal sensors in the supply tanks.
An alarm gong was also recorded followed by intermittent warnings relating to low rotor rpm. The penultimate warning recorded related to the battery discharging, which occurs when there is insufficient engine-driven generator power. The last warning related to an autopilot system failure. Investigation into the possible causes for the individual warnings is continuing.
HoHoHo said:
WinstonWolf said:
Wouldn't a pilot with this level of experience have auto rotated automatically in the absence of warnings?
That's exactly what I've asked but had no reply - I don't understand why he didn't As I've mentioned the blades weren't bent which indicates it literally fallen out of the sky and by not too high either based on the fact the cabin was still in tact.
saaby93 said:
If there are too many normal warnings eg at start up or due to cold tanks, it doesnt take much for an experienced pilot to learn to ignore the warnings
err... no.warnings/alarms are all categorized and prioritised, anything that was up as a startup event would not be still showing (assuming it was nothing catastrophic) - I assume you reading the line in the report about stored events?
Fuel gauges/warnings are shown at all times on the
like this:
CAD caution advisory display (upper part of CPDS)
(stolen image from PPRuNe)
fuel warnings are also audio-alarmed (as in they sound an alarm), it's hard to understand how one could miss them.
Scuffers said:
err... no.
warnings/alarms are all categorized and prioritised, anything that was up as a startup event would not be still showing (assuming it was nothing catastrophic) - I assume you reading the line in the report about stored events?
Fuel gauges/warnings are shown at all times on the
like this:
CAD caution advisory display (upper part of CPDS)
(stolen image from PPRuNe)
fuel warnings are also audio-alarmed (as in they sound an alarm), it's hard to understand how one could miss them.
I'm sorry to ask what might seem an obvious question, but would those alarms have to be manually silenced? I mean presumably they wouldn't just briefly sound and then switch off, would they? warnings/alarms are all categorized and prioritised, anything that was up as a startup event would not be still showing (assuming it was nothing catastrophic) - I assume you reading the line in the report about stored events?
Fuel gauges/warnings are shown at all times on the
like this:
CAD caution advisory display (upper part of CPDS)
(stolen image from PPRuNe)
fuel warnings are also audio-alarmed (as in they sound an alarm), it's hard to understand how one could miss them.
Another probably daft question, but would a pilot have any reason for not acting to move fuel from the main tank to the supply tanks? Thanks
The Spruce goose said:
The question i have is, why does the pilot have to manually move fuel, seems stupid.
I wondered about that too - I can understand that if the fuel level falls below a certain point that it becomes necessary to actively pump the fuel to the supply tanks. What I can't understand is why that isn't an automatic process. It seems to represent a kind of airborne Dead Man's handle, if you will forgive the analogy. TheSnitch said:
The Spruce goose said:
The question i have is, why does the pilot have to manually move fuel, seems stupid.
I wondered about that too - I can understand that if the fuel level falls below a certain point that it becomes necessary to actively pump the fuel to the supply tanks. What I can't understand is why that isn't an automatic process. It seems to represent a kind of airborne Dead Man's handle, if you will forgive the analogy. considering how critical fuel is to any aircraft, it has to be one (if not the) prime responsibility for the commander to be 100% aware of his fuel status at all times, these things have several independant fuel gauges/warnings, so even if one (or more) of them fail, you still have zero excuse for not managing it properly.
Looking at the reports we have so far, I cannot understand how this accident happened, all I can imagine is the pilot was either partially incapacitated, or really stuffed up in a major way.
to crash a 100% serviceable aircraft with plenty of usable fuel on-board in this way is in-excusable.
Scuffers said:
TheSnitch said:
The Spruce goose said:
The question i have is, why does the pilot have to manually move fuel, seems stupid.
I wondered about that too - I can understand that if the fuel level falls below a certain point that it becomes necessary to actively pump the fuel to the supply tanks. What I can't understand is why that isn't an automatic process. It seems to represent a kind of airborne Dead Man's handle, if you will forgive the analogy. considering how critical fuel is to any aircraft, it has to be one (if not the) prime responsibility for the commander to be 100% aware of his fuel status at all times, these things have several independant fuel gauges/warnings, so even if one (or more) of them fail, you still have zero excuse for not managing it properly.
Looking at the reports we have so far, I cannot understand how this accident happened, all I can imagine is the pilot was either partially incapacitated, or really stuffed up in a major way.
to crash a 100% serviceable aircraft with plenty of usable fuel on-board in this way is in-excusable.
''and I would guess it's so that you have to make a conscious decision to use the last ~30 mins of fuel in the main tank (as opposed to it just running out when it's 100% dry''
That makes sense to me.
What makes less sense is that 4 minutes prior to the crash, the pilot was in contact with air traffic control to get clearance, yet was not apparently aware of anything amiss at that time. I know that the data they have shows the alarms and other events without a time assigned to them, but it seems impossible to go from everything ok at 22:18 to catastrophic failure at 22:22.
I hope their further analysis of the data helps them form a clearer picture
Scuffers said:
these things have several independant fuel gauges/warnings, so even if one (or more) of them fail
and Scuffers said:
Looking at the reports we have so far, I cannot understand how this accident happened, all I can imagine is the pilot was either partially incapacitated, or really stuffed up in a major way.
The only way i can see for a human mistake is what i would call a "slight of hand" confusion by these multiple gauges in a manner to cause the pilot to misread the obvious signs. For example, if you have a single gauge or lamp, when that indicates, erroneously or not, "low fuel" you put the Helo on the deck ASAP, because you have no idea if it is accurate.With multiple sources of information, if they diverge (and there is currently some question as to the validity of some of the level warnings due to water contamination iirc) then i could just about imagine a scenario where a fully trained and high quality pilot is simply "tricked" into believing the wrong thing, ie that he has more fuel available than he actually does etc. Obviously in that case, the exact sequence and cascade of warnings and actions becomes critical for the holes to line up.
It does strike me, that a modern helicopter requiring pilot action to maintainn it's critical flight status is a bit silly, and automated system, with suitable low fuel warning surely is a better idea.
Secondarily of course, we have situation where an experienced and by all accounts expert pilot fails to carry off an suitable AR, and lets Nr decay catastrophically. Unfortunately, without CVR/CDR i suspect we will never know the full truth of what happened..... ;-(
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